Tank breather valve



Aug, 1% EH60 J. KUHL TANK BREATHER VALVE Filed Apr. 15 15925 gnue'ntoz l mented Aug, 1%, 1926. I

a v r was "s 4 ms fi es: lo s mmm p..-

JOHN KUY'IL, OF SAN LEEJANCISCO, GALiFORNIA, ASSIGNGEL are s'rannannorn cora- IA'NY, 9F SAN FRANCISCO; CALIFORITIA, A. CQRPORAFEON CALIFORll'IA.

TANK BEEATHEB VALVE.

. This invention relates to tank breathervalves and is more particularly directed to pressure and vacuum relief valves l'or use in connection with containers OfVOltltllBillllLl.

'lanks as now constructed for storing lioy uids suchjas petroleum oil and the products or the refining of petroleum oilhave for the most part gas-tight sealed roofs, which have introduced a particular problem of providing them with safe and sure means of venting. The air and vapor above the liquid surfaee'is subject toconsiderable expansion and contraction, with temperature variation, and

i also as the volume of gas varies with the'rise and fall of ti e liquid surface asthe volume oiioil in the tank is changed. the construction of the ordinary storage tankis not such as to Withstand the pressure developed. by' this expansion or contraction without provision for allowing escape and intake of gas or air through the roof. This might beaccomplished by means of an open hole in the roof, but this method defeats, in a measure, the purpose of gas-tight tank construction, namely the reduction of vapor losses and fire hazard. i

An object of this invention is to provide a means for automatically relieving pressure or vacuum in the tank or other container holding a gas or vapor which means are so designed that the relief .w-illhe eii ected when the pressure or vacuum reaches a pre ieterrained point.

Anobject this invention is to provide a pressure and vacuum relief means which. be placed on the roof of 'the'container, and which means are absolutely fluid-tight The nature of.

l ig. is a sectional side elevation of one of the relief valves embodying this invention.

Fig. is a {raginental sectional side elevation of the pressure v lie illustratedin Fin". 2, illustrating the eni rgency liquid seal blow-out valve removed and replacedby a cap. s

6 is a side elevation of the emergency liquid seal blow-out valve embodying this invention, and illustrating the same as at tachecl to a fragment or, pipe.

in the embodiment of this invention illustrated in the accompanying drawings, 1 in- (l which body a screw threaded opening 2 ii the bottom for a pipe connection to the tank or other container or system to which the valve is to be connected, the said body 1 having tapered opening 3 in the bottom or receiving the seats of the vacuum relief ,valve 5 and mailing a gas-tight connection until a certain predetermined pressure or,

- vacuum isreachedv Other ob ects and advantages of this in.- vention willberapparcnt from the following detailed description of a preferred embodi- 'inent thereof as illustrated in the accomanying drawings In the drawings:

Fig. 1 is a diagrammatic side elevation of a vapor line providing a communication be tween a pair of storage tanks and illustrating an embodiment of this invention.

Fig. 2 is aftop plan view oi a breather valve embodying this inve ."ion.

FlQj. is a siren sectional elevation. of the breather valve illustrated in illustrating the pressure and vacuum relic-i valve head in side elevation? body has a central passa between the main body 1 and the valve seat i, and also having a tapered opening 6 for receiving the seat a or the pressure relief valves 5 and making a gastight connection between the main body 1 and the seat i t-he body 1 also having a cylindrical bore 7 in the top for receiving the end 8 of the emergency liquid seal blow-out valve 9. A hood 10 is secured to the body 1 by any suitable meanajich as illustrated ll. The emer gency ll'fllld seal blowout valve 9 is preferably oi: the following construction: The or chamber 13 around which a ciroinferential channel 14 formed, which channel 142 is adapted to be filled with oil or other similar fluid. A. cover 15 having a cylindrical. extension l6- and a curved downwardly extending cap portion 17 is adapted to fit upon the body 12 with the cylindrical portion 1% fitting "within the chamber 14% to provide oil seal. A. phn'alityof equally ribs 18 are provided to rest upon the upner edge of the outer member forming the chamber Llso as to hold the cover properly spaced from the bodv so e provide lluirhpassage aznbei" 1- and up under .enal' can 17.

v lnis Y placing in i no. such as oil.

. the foregoing dothe pressure exerted by the i 1'1- 1 icates the main body of the breather valve,

might push the liquid under the lower edge of the cover 15 and thence upward and out of the channel. 1s, thereby causing" the loss of the liquid arid allowing the escape of the vapors at very low pressures. "in order to prevent the loss of the liquid and vapors at normal or other pressures not great enough to he dangerous, the channel 14- shohld he of such depth and tliesealing liquid should he of such specific gravity or density that the column of liquid in said channel i will not he forced out or" the channel at said normal pressures.

The pressure and vacuum relief valves 5 are preferably of similar construction and these valves serve to relieve the pressure or va'cuurn in the tank or container to which the breather valve is attached or connected whenever the pressure or vacuum reaches a predetermined amount. They can be designed to open at very slight pressure and they have a relatively large relieving capacity without materially increasing the pressure or vacuum in the tank. lhey have the advantage of 'lhfilllg tightly closed and. are not likely to stick; therefore the operation of these valves is very reliable.

The valve 5 comprises a cast seat 4 having a groove 19 for holding fluid, such as mercury, and having; a rib 20 with a cy linclrical core 21 which serves as guide for the valve stem 22. The outside of the valve seats a are tapered to lit the openings 3 and 6 in the main body 1, or may he made integral with the body It. The rib 20 is tapped to receive cap screws 23 for holding the dash pot 24 to the valve seat 4. The valve head is formed of light metal disc which seats into the mercury groove 19. To the center of the disc is secured valve stern 22 which is preferably in the nature oi? a hollow tube. To the lower end of the valve stem 22 are attached two wide cylindrical washers 26 between which a guide plate 21 is held. The dash pct 24 is preferably tilled with oil or like fluid so that the valve stein 22, the menu hers 26 and the disc plate'27 are immersed. A stop pin 28 passing through the valve stem 22 limits the opening of the valve disc 25 by coming in contact with the lower edge of the bore 21 through which the valve stem 22 passes. This dash pot arrangement serves as the lower guide for the valve stem 22 to prevent the valves 5 from chattering and thereby prevents the blowing out of H161 cury from the groove 19 and in general insures smooth operation when the valve is opening or closing. The operative pressure or vacuum on the valves 5 is determined by weight of the head 25 togetherwith the weight of the stem 22 and. its parts and is not dependent upon the depth of the seal formed in the mercury.

The valve seats i are maintained within the tapered openings 3 and 6 formed in the body 1 by any suitable or desirable means, such as screw-threading the came into position or the same may be maintained in position by means of a tight tapered fit. the

seats a being forced into the tapered bores 3 and 8 so that the same will not be dislodged by pressure from within the body 1.

ihe following illustrative example is given in order to enable those skilled in the art to which my invention pertains to more easily practice the same; it, however, being understood that this example is merely illustrative and subject to wide variations:

l-have found that the linear velocity of the vapors escaping through the valves 5 or 9 should he at least 700 feet per minute, in .order to prevent a dame from entering the valves and igniting the fluid within the container. The maximum allowable working pressure in any" ordinary oil storage tank of any capacity is about one inch of water pressure, or about 5.2 lbs. per square foot above atmospheric pressure.

ln the pressure and vacuum relief valves 5, the diameter of channel 19 is approximately 8% inches; the width of the channel 19 is inch; the depth of channel 19 is inch; the depth of liquid in channel 19 approximately inch. The liquid used is. I

this channel is gravity. 1

in the emergency relief valve 9, the diameter of channel le is approximately 22 inches; the depth of channel ll is 5 inches; the depth of liquid in channel 14 is approximately e inches. Liquid used in channel 14 is water or oil of specific gravity of ap proximately one.

in Fig. 1 is shown the manner in which these breather valves may he used in' connection with an oil tank vapor line, which vapor line is the subject of the conceding application of John M. Evans, filed Noveinher 20, 1924, Serial Number 751,103, where two of such breather valves are'shown connected to the top of the tanks A and B, which tanks A and B are connected by means of a vapor line C in such a manner that the excess vapor pressure developed above the surface of the oil in the tank A during the filling of the tank A. may he con' veyed through the line 3 to a tank B which is being emptied.

emergency liquid seal blow-out valve detached from the pressure valve body is illustrated as positioned in the vapor line C.

The 0 eration of this tank breather valve is such. t at when pressure is develcned within. the container to which the valve isottachecl the gas and vapor causing the pres: sure fiows upward through the co'. nection into the bod l and at a predetermined pressure raises t. e pressure relief valve 5 to the position illustrated in Fig. 3., or if a sudden or relatively large pressure is developed mercury of 13.6 specific till no i

within the container the liquid in the circumferential channel ll may be blown out and the pressure thereby vented to the atmospnere.

'lhe blowing out of this liquid serves as a warning to the tank field man or other person having charge of the container to which this pressure valve is attached. As soon as the gas pressure is discharged the pressure breather valve re-seats and when the liquid in channel 14: is replaced the tank is maintained closed. In case of a drop in pressure due to a drop of temperature or withdrawal of oil from the tank, a vacuum or reduced pressure is produced therein which reduced pressure is transmitted upward into the pressure valve body 1 and at a predetermined vacuum causes the vacuum relief valve 5 to open and allow air or other suitable gas to flow into the tank and relieve the vacuum, or if a sudden or relatively large vaciium is developed within the container. the liquid in the circumferential channel 14 may be sucked in and the vacuum thereby vented to the atmosphere.

The valve hoods and 15 are constructed with downwardly extending legs or caps to prevent Wind and rain from blowing di rectly against the valve liscin one case and against the liquid seal in the second case, so that the Wind or rain will not interfere with the operation of the pressure valve 5 or the chamber 14 of the emergency fluid seal blow-out valve 9.

A cover or cup 30 is adapted to tightly fit the bore 7 of the body 1 when it is desired in disclosed, which may he obviously varied within the scope of the appended claims.

I claim 1. A breather valve mechanism adapted to be connected to a fluid containing tank, comprising a body, pressure and vacuum liquid sealed relief valves mounted therein and adapted to relieve a pressure difference between the interior of the tank and the atmosphere of substantially 5.2 pounds per square foot, and an emergency blow-off valve detachably connected to the body and comrising a liquid seal adapted to be broken by the blowing outtherefrom of the maintaining liquid when the pressure within the said tank is suddenly increased to a pressure considerably greater than 5.2 pounds per square foot, an emergency valve etachably connected to the said body in open communication with the chamber and comprising a liquid seal, said liquid seal emergency valve including a base portion adapted to contain the liquid maintaining and consti tilting said liquid seal and a blowofl hood providing a valve head adapted to seat on said liquid containing base portion, said liquid seal being broken by the blowing therefrom of the maintaining liquid where the dilierence between the pressure in the chamber and that of the atmosphere is increased suddenly to considerably more than 5.2 pounds per square foot.

Signed at San Francisco, Calif, this 2nd day of April, 1925.

' JOHN KUHL.

men I 

